Norton 650SS

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Feb 22, 2007
I've taken some interest of late in this model, not sure why. Don't really know all that much about it. I sure like how it looks.

Robert Smith, of Motorcycle Classics (, writes, "The 650SS was essentially a stroked version of the model 99SS, with dimensions of 68mm x 89mm (the 99’s stroke had been 82mm). Like the top Dominator, the 650SS breathed through twin Amal Monoblocs, but with the intakes now angled downwards. Twin exhausts replaced the 99SS “siamesed” system, and the headlight nacelle was dropped in favor of matched speedometer and tachometer. Finish went from the 99SS two-tone color scheme to a classic black frame, silver painted tank and (optional) chrome fenders. Though simple in concept, the overall effect was stunning. The black, silver, polished alloy and chrome finish created “the look” for sports motorcycles for a decade — until the metalflake Seventies."

He continues, "Sadly, though, the Atlas always overshadowed the 650SS. After all, cubes are cubes, and the Atlas simply had more. The 650SS was last produced in 1967 — a year after AMC went bust and was acquired by Dennis Poore’s Manganese-Bronze empire — though a single carburetor version, the Mercury, continued until 1969."

When I Googled the bike tonight, one came up for sale. Price seems a bit high, but again, she is a good looking machine. ... otoID=1248

The description of the bike for sale is next to none. [Note, not affiliated in any way with the seller].

Sure has the classic Norton look.


Nice example, not stock, but nice. I had a 650 Manxman, it was really smooth and loved to rev, unfortunately, one rod sawed the case when it broke. I was told the 650s had fragile rods (duh) but with updated commando parts, they could last a lot longer.

Wrench, the 650SS is considered by many to be the pinacle of the Norton twin development, until the Commando came along. It was a 'hot-rod' and was the bike that was finally as fast or faster than the competition, the capacity of 650 was the largest that didn't produce too many unwanted vibrations. The Atlas and all of the pre-commando 750 variants had a bad reputation for vibration. The 650SS is considered a real classic hence the relatively high prices that they fetch. Good luck with your search.
Jean, Dave--

Thanks for the information. Not that it's any surprise, plenty of bikes I know nothing about, but for some reason I had missed this in Norton's development. Seems to have an almost Dominator-type tank. A clean looking design, too. I'm not really in the market for one, the Commando and the Ducati GT750 ('74) are taking all the extra time and cash at the moment :-o But if one of you guys/gals have one to give away, please advise.... maybe hewho has a spare one in his multi-floored warehouse?

Cheers and thanks again.

If you have a hankering for an earlier model Norton twin, consider a featherbed framed 88 (500cc) or a 99 (600cc) from the mid 50s. I personally think that they are more aesthetically pleasing than the later models with panels and trim bolted to the tank. They are not as fast as the later 650 and 750 models and hence don't seem to cost as much, but you already have arguably the fastest Norton twin with your Commando, so something different for pottering around could be a worthwhile addition to the stable.
Speeding is a nono now

I agree, speeding I think is a thing of the past, can't do it like we used to years ago. There are police everywhere and too many idiots driving cars and SUVs they can't handle. A smaller capacity Norton makes perfect sense and keeping one in running order is like having your own museum piece.

Good advice guys. Those are some gorgeous bikes. I'd imagine fetching one at a 'reasonable' cost is probably out of the question? The 99 has always held my eye. Definitely something to consider.


When I was commuting between my home in Kenilworth and the Marston Road factory, my "company hack" was a 650 SS. In many respects, I thought it was a better bike than the early Commando.

The only problems I had were a blown head gasket and a massive leak from the fitting that bolted to the crankcase and contained the oil feed and return pipes.

That particular failure resuted in a seized engine, as I cruised at about 85 mph along the M6 southbound on the way to work after a weekend at the family home in Leyland. Had to hitch-hike to Wolverhampton, then take the company van back to get the dead bike.

I think the hulk was still un-repaired a year later when the firm went bust.

We did a trial with a single carb on that bike, to see if there was better low-end torque for towing a sidecar. After the twin-Amals were replaced, the slides got swapped side to side. I had an interesting few seconds when the throttles stuck wide open just after I tucked in behind a bus in city traffic. I was glad of the magneto kill button right next to the throttle twist-grip!
I'm also quite interested in the 650SS and may have bought one yesterday. I'll find out for sure next week.

How was the 650SS for vibration at highway speed? (60-70MPH for me)
I knew Frank would have an anecdote and some observations for us. Any comments on the rideability of the 88 and 99 models, Frank? The mid-fifties ones are so beautiful to look at and don't seem to command the same prices as the much-sought after 650SS.
Looks like I bought the 650 SS. It was built late in 68, very near the end of production for ss bikes. It's a very sharp looking machine. The Fenders are not the deeply valenced ones found on earlier bikes, these look very similar to my Commando fenders.
What theat bike is selling at that price is the Featherbed frame.

Nice and clean, to be sure. Probably worth the money to the right buyer, of which I am sure there will be one before long.

If I remember right, that Bradsbikes page seems to have lots of cross listings from other websites. Not e-bay, but other websites that have bikes for sale sections...

IMHO, the Dominator 99 was the best of the bunch. It had the best compromise between performance and comfort. The 650SS was pushing the vibration envelope just a bit. It was eclipsed, of course, by the Atlas. The 600 cc twin was about the upper limit for vibration. The Domi 88 was even smoother, but gave away quite a bit in overall performance. I always thought the silver metallic paint and the chrome on the tank sides made for a very elegant piece of machinery.

On the Atlas, your toes and fingers went numb from vibration after 100 miles and we reckoned the headlamp bulbs only lasted 6000 miles. It didn't matter whether or not you actually used the lights, the vibration used to shake the filament off the posts in the bulb, hot or cold!

Really, the main development effort on the Commando was trying to get rid of the Atlas's vibration. The structural designers did some interesting things with the frame, not all sweetness and light, but it was a lot stiffer in the twisting axis than the Featherbed, and it kept the front and rear wheels together better. I never tested for vertical stiffness, but torsionally it improved about 10-fold over the Featherbed. Admittedly, those measurements were done with the bare frame (as instructed by management), and if I'd compared them with an installed engine and transmission, maybe the Commando wouldn't have shown up as well. I'm sure the Featherbed frame got a fair bit of stiffness from the engine.

As I've said before, we didn't have a good enough front brake to show up the problems with spreading of the downtubes that you modifiers have subsequently uncovered with your high-efficiency disc brakes.
Frank, My personal favourites from an aesthetic point of view is the mid 50s with painted/chromed tank and teardrop exhausts.
Many serious and succesfull classic racers swear that the featherbed is the more rigid and better handling frame when compare to the Commando. I like Commando handling, but I am willing to concede that the featherbeds I have ridden have a more solid 'planted' feel on the road. I suppose it goes to show that theory and reality do not always coincide, however as you rightly point out the main effort of the re-design was to tame the vibrations and I doubt that there will be any argument from anyone on this forum about the success of this exercise.
Congrats on the SS purchase, worntorn. You have to be excited as hell. The bike previously referenced on sold not long after it was listed here.... wonder if a fellow member here bought it?

Nice reading about the testing and evolution of these bikes from those on the inside. A real treat and education.

I'll probably be kicking myself about not having the spare $$$ to buy one myself --but have to admit, the advice of checking out the Dominator 99 instead is well placed.

I imagine with the strong UK £ over the U.S.D, a lot of these lovely machines will be crated and heading back to their birth-place.


My old boss at N-V, Peter Inchley, actually gave me a demonstration to compare the Featherbed (the works hack 650SS I was using) to the Commando.

We used the test track at the Motor Industries Research Accociation near Nuneaton. On the flat lanes of the high speed circuit, he was able to show how the Featherbed frame flexed in torsion, where the back and front wheels were being twisted relative to each other. The Commando didn't exhibit the same tendencies.

Of course we were riding the "factory fresh" prototypes, before the Isolastic spacer tube problem was found. Any rider comparison these days should with a properly set up Commando.

My structural testing was bare frame, and I was measuring torsional deflection between the headstock and the rear shock mounts on the seat loop and also to the lower Iso mount location. The engine/transmission and swing arm were not installed.

In retrospect, maybe we were'nt really comparing apples to apples, as we should really have checked rear wheel spindle to front wheel spindle, with the front forks installed too.
I told my friend Murray Neibel about my purchase of thev 650 SS and he got very excited. He has been looking for an SS for some time. He sells Suzuki now but was a Norton dealer back in the sixties when the SS came out. He tells me that very few came to the east coast and even fewer to the westcoast where we are.

He says that in the 1963 a friend took a 650SS to the Westwood racetrack in Vancouver (now gone) and it blew away the short stroke Manxes and G 50s. The only alteration from stock was removal of the cigar mufflers in favour of straight pipes.

The 650SS also won the Thruxton 500 in 62,63 and 64 (Phil Read and Brian Setchell)

I'm not expecting great speed or power from the bike(compared to an 850 Commando), but he is! He says expect less low end grunt but a much quicker revving engine, a result of the smaller displacement, relatively hot cam and high compression and the downdraft head/carb arrangement that the SS had.
worntorn said:
The 650SS also won the Thruxton 500 in 62,63 and 64 (Phil Read and Brian Setchell)

I'm not expecting great speed or power from the bike(compared to an 850 Commando), but he is! He says expect less low end grunt but a much quicker revving engine, a result of the smaller displacement, relatively hot cam and high compression and the downdraft head/carb arrangement that the SS had.

Sounds like a proper set-up to me. Any idea when you'll be able to report back on his ride report worntorn? It's of interest to me how the SS would compare in this regard to the Commando. In what I've read, also, these bikes were rare over here in the U.S. Of particular interest is the 'downdraft head/carb' arrangement you mention.

The bike was shipped today from Toronto and is expected to arrive here in vancouver on thursday. Not sure when I'll have it properly on the road, but I may sneak the commando plates onto it for a short ride.

The bike was stolen and wrecked in 1995. One of the Sarnia Vintage bike members, Herb Becker (of racing Commando fame, scroll to bottom of this page ) found the bike in a wrecker's yard and purchased it for a few hundred dollars. The thief had blown the engine when one throttle slide stuck wide open. The right side connecting rod went thru the right side case.
Herb donated the bike to the Sarnia Vintage group to be rebuilt and then raffled off. Terry Gower did the bulk of the work on the bike, but Herb and others in the group also helped. Lots of NOS parts were donated and the rest came from Mike at Walridge Motors. I talked with Mike and he remembered the bike well, or i should say he remembered the sale of a great many 650SS parts well.
After a long search a set of 650SS cases were found and purchased in Atlanta. Luckily the bikes original laft side case was undamaged, so the bike retained it's original engine number which matches the frame.

Terry told me they did not hold back on parts as they had a good budget with the raffle bringing in $16,000 and of course all labour was free.

The fellow who won the bike is not a motorcyclist, although he did obtain his motorcycle license after winning the bike. He learned that he is not that interested in motorcycling after putting just 1500 miles on the bike since 99. He said that he has not ridden it at all for few years, just started it up once or twice a year to keep things working.

The bike won 2nd place in Vintage class at the big Toronto Motorcycle show/swap meet in 99, so it comes with a trophy. Also included is an 18 page document that lists all of the work performed and new parts installed.
Terry said that the only weak point on the bike is the clutch cush rubbers which were quite worn but had to be reused as new ones were not available. He thinks new cush rubbers can be had now, so I will change them out.
worntorn said:
The bike was shipped today from Toronto and is expected to arrive here in vancouver on thursday.

Way to go worntorn.... would love to see pictures of your new acquisition if you care to share. The SS is just a gorgeous looking bike. Congratulations.

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